Update .gitlab-ci.yml - switch AGU to master

.gitlab-ci.yml

@@ -8,4 +8,4 @@ build-start:
   image: registry.gitlab.com/finestructure/pipeline-trigger
   stage: start
   script:
-    - trigger -h gitlab.cern.ch -a "$API_TOKEN" -p "$CI_JOB_TOKEN" -t dev -e JALIEN_ROOT_REPO=$CI_REPOSITORY_URL -e JALIEN_ROOT_BRANCH=$CI_COMMIT_REF_NAME 46440
+    - trigger -h gitlab.cern.ch -a "$API_TOKEN" -p "$CI_JOB_TOKEN" -t dev -e ALICE_GRID_UTILS_BRANCH=master -e JALIEN_ROOT_REPO=$CI_REPOSITORY_URL -e JALIEN_ROOT_BRANCH=$CI_COMMIT_REF_NAME 46440